Transmit-receive and shutter device electrode structure



R. S. BRADEN Dec. 10, 1957 TRANSMIT-RECEIVE AND SEUTTER DEVICE ELEcTRoDE STRUCTURE Filed oct. 25, 1955 2 Sheets-Sheet l Dezc; 10," 1957 R, s, BRADEN 2,816,272

TRANsMIT-RECEIVE AND SHUTTER DEVICE ELECTRODE STRUCTURE Filed oct. 25. 1955 2 sheets-sheet 2 INVENTOR.

RABYY s BEAEEN M4422 ATTORNEY United States Patentiilice 2,816,272 Patented Dec. 1,0, 21957 TRANsMrrfREoEIvEfANDzsHurrERmEvIoE; 4E-Lro'rkonrr@TimorUnit RayjS Braden;Melrpse,fMass., assignor to LBimiac Laboratories ^Inc.f,` Beverly, Mass., a Acorlmration of -Massa chusetsy Applicationictoher YZS, 1955,.Srial-,Noa542n28 comms. retrasa-13) devicefor 'protection 4of a'sensitive vradio receiver during* `v periods 'when a radio direction and ranging-system-'is Ainoperative. Togallow for normal "transmit-receive action during transmission of high'f power pulse magnetron energy, such Adevices 'are providedwith'` a-'side-*armeignitor electrode to csupply' a continuous source of electrons --in.

the discharge gapvto facilitate ionizationof-the"gaseous atmosphere ata predetermined voltage level. Since such side-arm electrode f' structureemploys aan vouter support member of iaidielectric material; suoh`assglass, it may be readily damaged during installati-onor.handling? It `is an object 'ofthe 'present invention to ,provide in a.transmitreceive gaseousdischargeltllbe a novelshlitter arrangement whichincorporates an ,enclosed.'l coaxial .lig nitor electrode structure.

A further object is to provide in a transmit-receive tube a novel shutter device which provides complete protection in the full attenuating position and serves as an ignitor electrode structure when normal tube operation is resumed.

A still further object is to provide a novel combination of a shutter-attenuator to short-circuit a discharge gap in a transmit-receive tube and a coaxial ignitor electrode within a unitary structure thereby improving overall construction and performance characteristics.

To accomplish the objects enumerated herein, I have discovered that the attenuating member of the shutter protective device positioned coaxially within the discharge gap electrode structure may be employed as an ignitor electrode when the attenuator is withdrawn from the short-circuit position. In this position, the attenuating member which is electrically insulated from the electromagnet and tube envelope contacts electrically conductive means to impress a desired ignitor electrode voltage thereon. The tip of the attenuating member will then be positioned in close proximity to the apex of the conical discharge gap electrode at approximately the same critical distance as a common ignitor electrode in a transmitreceive tube. It will thus be evident that a source of electrons will be introduced into the discharge gap region when the attenuating member is conductive to thereby par tially ionize the gaseous atmosphere.

Other objects, features, and advantages will be readily apparent after consideration of the following detailed specification and accompanying drawings in which:

Eig. l is a perspective View partly in section of the i1- '22 lustr'ative' embodiment withe dttedlihesf'f inditzfating:A the overallfconiigurationf 1 s Fig:` 2 is an.' enlrgesdf longitudinal lcross-sectional 7view of ;"`the illustrative `'erirbdiment-"*iiither nonattenuating c position;

"Fig-"3 *is *a perspective view 'of an alternative lembodi- 'mentg arid*V l Figgy 4 is alongitudinal"cross=sectional'view of thetalternativeembodiriientz. p Referring-Jo' the` drawings thecombinatiomtransmitreceivev and {shutter-device 'is' l shown* generally at 1 *and comprises `a^lengtl1l of @rectangular -waveguide l2""having secured aty `the;` endstthereof connecting llan'ges-"S and 4,

"eachhaving `:afresonant'wiiidiw'element-5,'-to"`provide a "-hermeticallysealed'envelope: 'The device is filled-'with lan ionizable jatmosphbre comprising a `lmixture of an inert `gas-such'zasrhydogen,"V argon; ornitrogen, and 4'asmall percentage 'offwatervapor'ata "total` pressure off'approximately 5 to 10 millimeters vofmercuryr""Resonant Vdis- '-y charge; gap electrodes '6*and'"7'=are Vmounted twit-hingwaveguideZ toit define ther'ebetween-- acfdischarge'I gapn in the manner vjdescribed-ini United States Patenti 2,680,207 and the aforementioneddapplication: Inductive lmetallic 'partitiontmembersSand@ are' also disposed 'within said wave- Y* guide? to l`provide a vresonant irs'rin" a manner vwellfknown Theshuttenattenuatormember 10fof-the embodiment is lslidably' disposed iwithinfa-ih'ollow passagewayefinigap electrode 6 and is formed''offa-conductivemetal. vkTofiso- -5late the attenuator member-10 tromtheenvelope,"a'sleeve j11"of"a@non-conductiveinsulating 'material 1is positioned ine-the Ypas'sagewa-yfofelectrode56; "Inythe iattenuatingpo sit-ion, attenuator member io-extendsaerlessfthe discharge gapto contact the opposed electrode'f`7. "Structure-for -fretractionoffattenuatorimember 10 is similr'fto that described'irtheaforementioned applica- Springflvurges said' armaturedownwardly#V tojretu'rnethe 40Qme`rber-to its'fatter-1uating*positinewhbnJ theelectromagnet is de-energized. Leads 15 and 16 are provided for connection of the electromagnet to a suitable energizing circuit of approximately 15-30 volts either direct or alternating current. Inasmuch as the core of the electromagnet is provided with a passageway to receive the upper portion of member 10, I next insulate said member from the electromagnet circuit and the envelope by a liner 17 in the passageway and washers 18 and 19 all of a suitable insulating material.

To transform the attenuator member 10 into a coaxial ignitor electrode, which is one of the principal advantages of the invention, electrically conductive contact means are contained within electromagnet 12 of the illustrative embodiment. The passageway within the electromagnet 12 is enlarged at its upper end as 20 with a threaded plug 21 enclosing the end thereof. A vacuum seal between the walls of insulating liner 17 and plug 21, which may be of a conductive metal such as copper or brass is achieved by metallizing the inner wall of liner 17 in the area of contact and then brazing the pieces together in a manner well-known in the art. An electrical connector 26 may then be fastened around the threaded shank of plug 21 and retained in position by nut 22. To the underside of metallic plug 21, I aix a Ispring 23 and a contact plate 24 which is in turn ailixed to the spring.

In the non-attenuating position as shown in Figure 2, with the electromagnet energized, armature 13 will move upwards until it rests against insulator washer 18. This in turn moves attenuator member 10 to a position within hollow electrode 6 with a critically short distance 25 between the tip of attenuator member 10 and the apex of hollow electrode 6. The upward movement further re! sults in the upper end of attenuator member contacting able resistance in the circuit. This current is customary for ignitor electrodes in the transmit-receive tube art and will result in partial ionization of the gaseous atmosphere to supply a source of electrons in the discharge gap prior to transmission of high power magnetron pulses. It will thus be evident that the attenuator-shutter member 10 can be employed to serve in an additional capacity as an gnitor electrode when it is in the non-attenuating position. The eliminates the need for any auxiliary electrode structure now commonly employed in the TR art.

inasmuch as the attenuator member is conductive in the ignitor position, it is desirable to insulate armature 13 from the upper inside walls of electrode 6 to prevent any arc-over. For this purpose, I provide a dielectric cup member 2S within this portion of electrode 6. Alternatively, a coating of an insulating material may be provided on the exposed wall surfaces.

Alternative contact means are shown in Figures 3 and 4. In this embodiment end plug 21 may be fabricated with a-plurality of preformed fingers 29 of a material such as beryllium copper extending from the under side thereof. When member 10 is moved upwardly the fingers will firmly engage the shank as shown in Figure 4. The pressure of the fingers should be adjusted so that the member 10 may be quickly returned to the attenuating position by the spring 14 which is compressed when the member 10 is in the electrode or upward position.

Other modifications or alterations may occur to those skilled in the art. It is, therefore, my intention to cover in the appended claims such modifications or alterations as fall within the spirit and scope of the invention.

What is claimed is:

1. A microwave shutter and transmit-receive switching device comprising a hermetically sealed envelope containing a gaseous atmosphere, spaced opposed electrode structure defining a resonant discharge gap mounted within said envelope with at least one of said electrodes having a hollow passageway therethrough, a metallic rod element slidably disposed within said hollow passageway and extending across said discharge gap to Contact the opposed electrode when in full attenuating position, electromechanical means mounted on said envelope to retract said rod element to a position within said hollow electrode, means positioned within said electromechanical means to contact the upper end of said rod element in its retracted position, said contact means including a springbiased plate member electrically connected to a direct current voltage source to thereby transform said rod element into an auxiliary ignitor electrode with a voltage potential impressed thereon sufficient to partially icnize said gaseous atmosphere.

2. A microwave shutter and transmit-receive switching device comprising a hermetically sealed envelope containing a gaseous atmosphere, spaced opposed electrode structure defining a resonant discharge gap mounted within said envelope with at least one of said electrodes having a hollow passageway therethrough, a metallic rod element slidably disposed within said hollow passageway and extending across said discharge gap to Contact the opposed electrode when in full attenuating position, electromechanical means mounted on said envelope to retract said rod element to a position within said hollow electrode, said electromechanical means having an axial passageway therethrough with a contact member disposed at the upper end thereof, said contact member being electrically connected to a direct current voltage source of between 500 to 800 volts to thereby transform said rod element into an auxiliary ignitor electrode when in its retracted position, a liner of an insulating material within said electromechanical means passageway and hollow electrode to prevent leakage of current when said rod element is in contiguous relationship with the electrically conductive contact member.

References Cited in the file of this patent UNITED STATES PATENTS 2,499,777 Pound Mar. 7, 1950 2,520,604 Linder Aug. 29, 1950 2,524,268 McCarthy Oct. 3, 1950 2,734,171 Heins Feb. 7, 1956 

